Supposedly Himiko Toga can copy for a short period (a day or so) another person's appearence. But also, while experiencing intense emotions, she can replicate quirks. Yet, if I understood correctly, she could replicate Ochako's quirk long after she copied her , many days after that happened. How does Himiko Toga quirk replications habilities work? Is she capable if having strong emotions to use any person quirk she copied long time ago?
From the wiki,
The amount of time the Quirk allows one to stay transformed is proportionate to the amount of blood that is consumed. One cup of blood equates to roughly one day’s worth of transformation. If the blood of multiple people has been ingested in one go, this will allow the user of the Quirk to transform into any of them, without having to return to their original shape between transformations.
With enough blood, yes, she can transform to anyone even days after she ingested them. If I understand correctly, the quirk of the user she copied can only be used as long as she stays transformed and as long as she understands how it works. So, if she's within the time that her ingested blood allows her to, she can still copy the quirk of someone.
Also recall that she did not copy Ochaco initially but rather, drained her blood and fled. She copied her days after. I'm not sure if this was stated but the quirk's description seems to imply that the time limit of copying someone starts and ends only when she changes into them, regardless of when she ingested their blood.